Jessica, 34, posted a photo via Instagram, showing a beautiful printed shot of her sister.
Ashlee stares straight into the camera in the stunning image, looking ethereal and pretty with her blonde locks in an intricate braid. She wears white drop earrings and is dressed in a sparkling loose top.
"Happy Birthday Ashlee!" Jessica captioned the photo. "There is no one I believe in more than you. Thank you for inspiring me everyday. I love you!!! #dirty30"
It's an exciting time for Ashlee, who turned 30 on Friday, as she married her actor love Evan Ross on Sunday, Aug. 31. After getting engaged this past January, the pair honeymooned in Bali together last month.
Jessica also recently tied the knot, marrying Eric Johnson, who is the father to her two children, this past July. She served as a bridesmaid at Ashlee's wedding, while her daughter Maxwell was the flower girl for her aunt.
Sign up now for the Us Weekly newsletter to get breaking celebrity news, hot pics and more delivered straight to your inbox!